Abstract by Merlin Hart
Physics and Astronomy
Effect of Storage conditions for Thin Film reflectance
Fluoride capping layers are currently used as the final layer for space observatories with far UV (FUV) sensitivity. For example, Hubble Space Telescope uses 25 nm of magnesium fluoride on aluminum and can see down to the important Lyman alpha line (121.2 nm). (Only Al has far UV reflectance.) Lithium fluoride (LiF) is better option for seeing further into the FUV, and is the choice for the next generation of space telescopes. However, it is hygroscopic. While some LiF on Al thin films can reflect well out to Lyman beta (102.6 nm), longevity is an issue. Spectroscopic ellipsometry is useful in study oxide growth under MgF2 and AlF3 on Al thin films. I am studying the aging of thin LiF on Al films that I have prepared on room temperature and heated substrates, the best conditions are to store thin LiF films, and the effect of plasma cleaning.